With this game and Indycar Racing Papyrus covered the two most popular American racing series which see up to today frequently appearing new versions (NASCAR 4 being the latest).
Nascars are very simplistic yet powerful stock cars which run mostly on ovals. Although not as fast as Indycars they are quite sturdy and durable and this is absolutely necessary because NASCAR races are endurance races which can last up to 3 hours pure racing time and more.